The Productivity of Fish Food in Oneida Lake 163 



crowded rays of radiata. The radiata of Oneida Lake are not 

 typical, being more inflated, quadrate in outline rather than 

 elliptical, the rays are not as even or as numerous and the color 

 of the shell is usually yellowish rather than greenish, in this 

 respect approaching luteola. Only a very few typical shells of 

 radiata were collected, this type in the lake showing a decided 

 variation toward the race herein listed as oneidensis. 



13. Lampsilis iris (Lea). Not collected in 1916. 



Genus Nephronajas Crosse and Fischer 



14. Nephronajas ligamentina (Lamarck). 



Diligent search failed to bring this species to light, one speci- 

 men of which was obtained in 1915 (Baker, '16, p. 259). 



order teleodesmacea 



Family Spii/ERIid^ 



Genus Spii.erium Scopoli 



15. Sphasrium striatinum (Lamarck). Not collected in 1915- 



16. Sphaerium vermontanum Prime. 



This is the most abundant of these small clams, occurring 

 in water from one and a half to four feet deep and on all 

 varieties of bottom except boulder. It is subject to some varia- 

 tion and, according to Dr. V. Sterki, has been little known 

 until recently. All ages were collected, from young to mature, 

 though the latter were rare at this time of the year (July) the 

 majority of individuals being young or immature. It was most 

 abundant on a sand bottom in one and a half to four feet of 

 water. 



*i7. Sphaerium solidulum (Prime). 



This species occurred somewhat sparingly in water 8 to 18 

 feet deep on a mud bottom. Dr. Sterki characterizes it as a 

 small eastern form. 



*i8. Sphaerium sulcatum (Lamarck). 



Found only on a mud bottom in 8 to 13 feet of water. It is 

 the rarest of these small clams and is a small, slight form, 

 (]uite unlike the large, heavy individuals found in other parts 



